The sponsorships for Tony Stewart could hinge on the outcome of the investigation into the death of Kevin Ward Jr. / Kevin Liles, USA TODAY Sports

by Nate Ryan, USA TODAY Sports

by Nate Ryan, USA TODAY Sports

HAMPTON, Ga. â?? One of Tony Stewart's primary sponsors reaffirmed its commitment Sunday to the NASCAR star, citing "overwhelming" public support as Stewart remains under investigation in a sprint car driver's death.

The Oral-B USA 500 at Atlanta Motor Speedway marked Stewart's return to the No. 14 Chevrolet after missing three Sprint Cup races while grieving for Kevin Ward Jr., whom he struck and killed in an Aug. 9 race at Canandaigua (N.Y.) Motorsports Park.

Ontario County Sheriff Philip Povero said Friday his department's review of the incident would continue for at least two more weeks. Though no sponsor has pulled its support of Stewart-Haas Racing, Exxon Mobil has downsized advertising and promotional campaigns that feature Stewart, who appeared Friday at a news conference in a black polo shirt devoid of corporate logos.

There's been no change in the marketing plan for Rush Truck Centers, the primary sponsor of Stewart's car in five races in NASCAR's premier series this season. W.M. "Rusty" Rush, the CEO, chairman and president of the truck dealership company (which is headquartered in New Braunfels, Texas, just outside San Antonio), said he attended the Atlanta race in a show of respect for the team.

"We stand by Tony," Rush told USA TODAY Sports. "That's why I'm here today. It was a terrible accident. It was a tragedy. Obviously like anyone, we're sitting back and waiting for the investigation (to be completed). At the same time, we see nothing right now that would change our relationship with Stewart-Haas."

Rush's marketing department has been monitoring feedback through email, its Facebook page and other forms of social media.

"It was an accident, and we find that's the way it's been viewed, at least by our customer base," Rush said. "You're going to have a few negative comments, but it's been overwhelmingly in support of our sponsorship, of SHR and of Tony."

Founded in 1965, Rush Enterprises (the parent company of Rush Truck Centers) was taken public in June 1996 and has 6,000 employees spread across 106 dealerships in more than 20 states.

Rush said he had talked to some on the company's board of directors and his executive staff, but there had been no meetings to re-evaluate its NASCAR sponsorship, which continues through the 2015 season.

"You do what's right, and in my mind, it was a tragic accident," Rush said. "I feel for Tony, and I know he's really grieving and hurting a lot. We see nothing that will change our position. Everyone is in support of where we're at now. I'm here as a friend but also to show the support of the organization."

Rush said his company briefly had been in contact with some of Stewart's other sponsors.

"A little bit, but we would like to keep that between us," he said. "I think everyone has been pretty much in the same mindset of letting everyone breathe and get through the healing process and at the same time, monitor the situation with the investigation."

Rush wouldn't comment on how the sponsorship would be affected if criminal charges were filed against Stewart.

"Speculation wouldn't be proper at this time," he said. "Let the investigators take it one step at a time."

Rush Truck Center's primary sponsorship of Stewart's car began with three races last season, growing out of the company president's longstanding friendship with Stewart (whom he met seven years ago through selling trucks to Joe Gibbs Racing, Stewart's former team).

"From the perspective that sometimes people lose sight of who that man is in that car, I've seen him do more charitable things than anyone," Rush said. "He's got a heart that people don't understand. Everybody just sees Tony. They don't know Tony. I can't tell the countless times I've watched him give this year. He's got a big heart and as much of a passion as anyone I've ever known."

Rush said the company's No. 1 concern was the well-being of Ward's family.

"Speaking for Rush Truck Centers, Rush Enterprises and myself, obviously our deepest sympathy goes out to them as they go through the healing process," he said. "It's difficult and devastating on the Ward family, but I know how hurt Tony has felt. I grieve for both sides, if that makes sense."

The sentiment echoed that of a statement released Saturday by Johnny Morris, whose Bass Pro Shops company is sponsoring Stewart's car at Atlanta.

"Today our thoughts are with our friend and fishing buddy Tony Stewart as he prepares to return to racing after what has been a difficult time in his life," Morris, who also was expected to attend Sunday's race, said in the release. "Our hearts go out to him and to the family and friends of Kevin Ward Jr.

"I was able to spend time with Tony last week and it made my heart ache to see him so devastated by this incident. Like many other race fans, I love Tony's passion and skill on the track and to watch this fierce competitor compete. But the off-track Tony Stewart is the man whom I have come to admire. Time and time again, I've witnessed Tony's quiet generosity and compassion as he gives to others.

"By personally supporting numerous programs like Catch-A-Dream Foundation and Victory Junction, Tony has given many ailing children a chance to experience outdoor sports and have fun opportunities they might not otherwise have. â?¦ What started as a sponsorship discussion between Tony and I fifteen years ago has turned into a long and special friendship. It's a friendship that has let me get to know one of the most compassionate and kind-hearted people I have ever met. On behalf of the Bass Pro family, and as Tony's friend, we are proud to stand by him as he returns this weekend to the sport he loves so much."